Spray-on-and-wipe-off cleaning compositions are well known in the art. See, for example, U.S. Pat. Nos. 3,463,735 to Stonebraker; 4,302,348 to Requejo, and 4,606,842 to Keyes, et al. The spray-on-and-wipe-off compositions of the prior art typically include a solvent, for example, a mixture of isopropyl alcohol and ethylene glycol monobutyl ether, a surfactant, for example, sodium lauryl sulfate; a builder, for example, tetrasodium polyphosphate or a water soluble polyacrylic acid resin; an alkalinity agent, for example, ammonium hydroxide and morpholine, or an acidity agent for example, acetic acid; adjuvants such as a dye and a perfume; and water. Compositions including the alkalinity agent typically have a pH of between about 8.5 to about 11.5,while composition incorporating the acidity agent typically have a pH of from about 2.5 to about 6.5.
It has been found that there is a tendency of the colorant, most typically a water soluble dye, present in these known compositions to fade in such compositions. It is believed that the tendency for the colorant to fade is attributable to impurities present in the composition, primarily impurities associated with the glycol either-type solvent, especially when such solvents are incorporated at higher concentrations. Concentrates of such compositions intended for dilution with water prior to use are especially susceptible to this dye fading problem. Fading of the colorant is not only unattractive to purchasers of the product, but makes the product less visible when applied to the surface to be cleaned. Accordingly, there is a definite need to at least substantially reduce the rate at which the colorant fades. It has been found for such compositions having an acidic pH that incorporation of oxalic acid in effective amount is satisfactory to stabilize the colorant in such compositions. Also suitable is the incorporation of an oxalate salt that provides in acidic media an effective amount of the oxalic acid as an equilibrium species.
Accordingly, it is an object of the present invention to provide a spray-on-and-wipe-off hard surface cleaning composition having an acidic pH containing a colorant stabilized against color fading.
It is a further object of the present invention to provide such hard surface cleaning composition, in concentrate or ready-to-use form, containing a level of a glycol ether solvent having destabilizing concentration of dye-interactive impurities.
It is a further object of the present invention to provide such stabilized dye hard surface cleaning compositions wherein the stabilizer for the colorant is oxalic acid.
Yet another object of the present invention is to provide hard surface cleaning compositions compatible with PVC containers.
An additional object of the present invention is to provide hard surface cleaning compositions exhibiting improved cleaning performance.
These and other objects and advantages of the present invention will be apparent upon a reading of the entire disclosure, a summary of which appears below.